Epstein-Barr virus (EBV) is a human herpesvirus that infects a large majority of the world's population. EBV is implicated in a wide range of diseases, including infectious mononucleosis, several types of cancers, and multiple sclerosis. Therefore it is important to identify means to inhibit viral replication, especially for those at risk of EBV-related malignancies, such as immunocompromised patients and transplant recipients. Here we propose to investigate the inhibition of EBV lytic replication imposed by the suppression of mTOR activity. mTOR is a key regulator of protein translation, autophagy, and cell growth. We have previously determined that inhibition of mTOR by rapamycin significantly inhibits EBV lytic replication in B cells. We have found that in epithelial cells, however, lytic replication is not inhibited, it is in fact enhanced by mTOR suppression. Our goal for this proposal is to determine the mechanism by which suppression of mTOR alters EBV lytic replication, as well as to ascertain whether inhibition of the cellular mTOR pathway is a viable option for treating EBV-positive tumors in cancer patients. The specific aims of this proposal are #1) to determine how the mTOR pathway alters the functions of the EBV immediate early proteins BZLF1 and BRLF1, and whether such alterations are cell-type specific, and #2) to determine whether EBV itself manipulates the mTOR pathway to promote viral replication. To carry out these specific aims, we will analyze, at the protein level, the responses of EBV-positive cell lines to inhibition of th mTOR pathway, as well as the effects of EBV lytic replication on mTOR pathway components. Inhibition of the mTOR pathway has been previously proposed as a possibility to treat EBV-related lymphomas. Our research aims to determine the cell-type specificity of this inhibition, as well as the mechanism behind this inhibition. The outcomes of this research will impact the feasibility of using mTOR inhibitors to control EBV-related cancers. PUBLIC HEALTH RELEVANCE: Epstein-Barr virus (EBV) is a widespread human herpes virus which is associated with several types of cancer, most notably lymphomas. Our research addresses how the mTOR pathway is involved in EBV replication, and how inhibition of mTOR activity inhibits EBV lytic replication. The goals of this study are aimed at assessing the abilityof mTOR inhibitors to prevent EBV lytic replication in different cell types, as well as determining the mechanism by which these inhibitors inhibit EBV lytic replication.